[shorod]

Welcome to the forum!

When you talk about the "threads" I believe you are actually referring to the exhaust manifold studs, correct? Yeah, it can be tough in some cases to get the studs out without breaking them. And of course other times the studs will spin out when trying to remove the nut. If you are concerned with actually removing them, then a wire brush on a drill would likely work, but you'll want to plug up the exhaust ports so you don't get all that debris in to the ports and possibly in to the cylinders. My personal preference would be to use a die (such as what's in the thread restorer kit) and chase the threads. It may be worth double nutting a few of the studs though once the manifold is removed to see if you can back the studs out relatively easily, then replace them. I'm not sure you'd want to go with anodized though as there may be a galvanic reaction between the manifold and anodized nuts. I don't know metallurgy well enough to proper address that risk though. I would probably just go with OEM studs and nuts and be sure to use anti-seize when reassembling.

-Rod